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%I #8 Jul 21 2020 11:48:15
%S 1,11,127,221,367,-1895,1447237,-57253,118526399,-5749677193,
%T 91546283957,-1792042789427,1982765468376757,-286994504449237,
%U 3187598676787485443,-4625594554880206360895,16555640865486520494719,-22142170099387402072693,904185845619475242495903560731
%N a(n) = Numerator(-2*n*HurwitzZeta(1 - 2*n, -1/2)) for n > 0, and a(0) = 1.
%F a(n) = Numerator(Bernoulli(2*n, -1/2)).
%p a := n -> numer(`if`(n=0, 1, -2*n*Zeta(0, 1-2*n, -1/2))): seq(a(n), n=0..18);
%t a[0] := 1; a[n_] := -2 n HurwitzZeta[1 - 2 n, -1/2]; Array[a, 18, 0] // Numerator
%o (PARI) a(n) = numerator(subst(bernpol(2*n, x), x, -1/2)); \\ _Michel Marcus_, Jul 21 2020
%Y Cf. A033469 (denominators), A001896 (evaluated at x=+1/2).
%K sign
%O 0,2
%A _Peter Luschny_, Jul 21 2020